1. Field of the Invention
This invention relates generally to telecommunication wiring systems for use in the communications industry. More specifically, this invention relates to an improved wiring connecting system having superior electrical transmission performance with reduced cross talk and improved lacing and termination features.
2. Prior Art
Prior art wire connecting systems or wiring blocks are well known and commercially available from ATandT, now Lucent Technologies, Inc., as the 110 connector system. The 110 wire connecting systems are described in several patents including U.S. Pat. Nos. 3,611,264; 3,798,581 and 4,118,095. The 110 type wiring block comprises a base having a plurality of legs at each end thereof. The legs provide a space behind the wiring block (when mounted) for cables that are to be terminated on the wiring block. The wiring block includes a base having a plurality of spaced longitudinal slots. A wiring strip is secured to the base within the slots by a plurality of posts. Connector blocks having Insulation Displacement Contacts (IDC""s) housed within are mounted on the wire strips. Wires terminated at 110 wiring blocks may be terminated at the wiring strips and at the connector blocks for electrical contact with the IDC""s of the connector blocks. The use of IDC""s in which the wires are punched into the IDC maximizes density and facilitates ease of use. Various improvements to such 110 connector systems have been made since their initial development, including the feature of using detachable legs, as described in U.S. Pat. No. Re. 35,030.
In a typical wiring application, backbone cabling (such as from outside a building or from a main bus within the building to a particular floor) is terminated at a primary distribution point where 110 wiring blocks are employed. Horizontal cabling from various end-user equipment or communications networking, e.g. computers, phones, networks and the like, is also terminated at the distribution point at 110 wiring blocks. The 110 type connecting systems are designed to support digital data transmission as well as analog/digital voice over unshielded twisted pair (UTP) media through the use of wiring blocks, connector blocks and patch cords or jumpers. This system facilitates moves, additions and rearrangements of circuits connected to end-users or equipment to provide a flexible means of connecting horizontal and backbone cabling within a building.
With increased rates of transmission, a higher performance wiring block is needed to minimize near end transmission cross talk between IDC pairs. The problem of cross talk is not very severe at low frequencies (around 16 MHZ), however, as the rate of transmission increases up to 400 MHZ, the radiation is higher and there is a greater need to reduce this cross talk. Prior art attempts to reduce this cross talk have utilized conductive shields (plates) between pairs. U.S. Pat. Nos. 5,160,273, 5,324,211 and 5,328,380 are examples of the use of such plates. However these prior art attempts do not surround and/or isolate the IDC pairs and thus reduction of cross talk is not optimized. Another limitation of these prior art devices is that difficulty is encountered when lacing and punching down twisted pair wiring. The tips of the 110 type blocks between the IDC pairs are typically blunt and require untwisting of the wire prior to lacing into the block. This leads to excessive untwist in the pair and loss of electrical performance. Thus, there is a need in the industry for an improved wiring connecting system having superior electrical transmission performance with reduced cross talk and improved lacing and termination features.
The above-discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by the wiring connecting system of the present invention. In accordance with the present invention, a wiring connecting system having an improved wire strip, connecting block, and cross-talk barrier is disclosed. The wiring connecting system includes a base, a wire strip mountable to the base, a connecting block for housing a plurality of electrical contacts and a plurality of cross talk barriers disposed within the connecting block for isolating pairs of the electrical contacts.
The wire strip has a plurality of first and second posts alternating along its length. The second posts have a greater width than the first posts. The first posts and second posts define an opening to receive a wire therebetween. A connecting block for housing a plurality of electrical contacts mounts onto the wire strip. The connecting block is made of an insulative material and includes opposed sidewalls and opposed upper and lower ends. The upper end includes a plurality of first and second teeth alternating along its length. The second teeth have a greater width than the first teeth. A space is provided between the teeth to receive a wire. The electrical contacts are partially disposed within the space and extend from the lower end of the connecting block to generally align with the openings of the wire strip. A plurality of barriers for electrically shielding pairs of the electrical contacts are disposed within the connecting block housing and substantially surround respective pairs of the electrical contacts.
In a preferred embodiment, the barriers include depending legs which seat within the second posts of the wire strip. The barriers may also include extending arms which nestle within the second teeth of the connecting block.
A plug for connecting a cable having a plurality of wires to the connecting block is also disclosed in accordance with the present invention. The plug includes a housing having a first end, a second end and a hollow interior. The first end has a hole to receive the cable and the second end has a plurality of openings which are generally aligned with the spaces between the first and second teeth of the connecting block so that the electrical connectors disposed within the housing interior can electrically connect to the electrical contacts housed within the connecting block when the plug is mounted to the connecting block. In another embodiment the electrical connectors are either J shaped or C shaped to reduce transmission loss within pairs of the electrical connectors. A shield may be disposed on a side of the plug to alter the magnetic fields associated with the wire contact pairs to further reduce cross-talk.